Means for and method of operating the needles of warp knitting machines

ABSTRACT

MEANS FOR AND A METHOD OF OPERATING PIVOTED LATCH NEEDLES OF A WRAP KNITTING MACHINE ALONG A KNITTING PATH IN WHICH THE LATCH OF THE NEEDLES ARE OPENED AND HELD IN OPEN POSITIONS BY THE STICHES OF ONE COURSE OF A FABRIC FORMED BY THE NEEDLES WHILE YARN IS LAPPED AROUND THE NEEDLES FOR THE NEXT COURSE OF STICHES OF THE FABRIC.

March 16, 1971 J. 0. WENRICH 3,570,269

'MEANS FOR AND METHOD OF OPERATING THE NEEDLES OF WARP KNITTING MACHINES Filed May 5, 1969 2 Sheets-Sheet 1 P .I. E E P .15- 30 30 1,71% 3/ MM'Ch 1971 J. D. WE ICH 3,570,269

MEANS FOR AND MET 0F ERATING THE NEEDLES OF WARP TTING MACHINES I Filed May 5, 1969 2 Sheets-Sheet 2 United States Patent Int. Cl. D04b US. CI. 6686 4 Claims ABSTRACT OF THE DISCLOSURE Means for and a method of operating pivoted latch needles of a warp knitting machine along a knitting path in which the latches of the needles are opened and held in open positions by the stitches of one course of a fabric formed by the needles while yarn is lapped around the needles for the next course of stitches of the fabric.

BACKGROUND OF THE INVENTION Conventionally in warp knitting machines having pivoted latch needles the needles are operated along a knitting path from a low level in which the needles have drawn yarn for a new course of stitches and a previously formed course of stitches have been knitted or knocked off the needles to a high level during which movements the stitches of the new course while held in the throats of the sinkers of the machine, first open the latches of the needles and then are cleared below the opened latches, and yarn is then lapped around the needles by yarn guides for the next course of stitches. Inasmuch as the stitches of each newly formed course are cleared below the latches of the needles before the yarn guides complete their yarn lapping movements for the next course of stitches the pressure applied by the stitches on the open latches as they are cleared therebelow, tends to cause the latches to tfiy and inadvertently close over the hook portions of the needles. When this occurs the yarns are lapped around the closed latches and no stitches are formed by the needles.

Heretofore, in order to prevent this inadvertent closing of the needle latches the machines were also provided with guard means for the latches in the form of a wire rod which was mounted in the sinkers, as disclosed in US. Pat. No. 2,810,278 or in the form of a fiat bar as disclosed in British Pat. No. 913,823. The guard means of both patents were movable to an active position to intercept and prevent the latches of the needles closing as the stitches of each newly formed course were cleared below the open latches and to an inactive position to permit the latches to be closed by stitches of the new course as the needles were lowered to draw yarn for the stitches of the next course and knock off the stitches of the previously formed course.

The instant invention has for its principal object the elimination of the guard means described above and the substitution of a method of and a means for operating pivoted latch needles of a warp knitting machine in such manner that the stitches of each new course open and hold the needle latches open while yarns for the next course of stitches are lapped around the needles.

SUMMARY OF THE INVENTION Briefly summarized the invention resides in the provision of means for and to the method of operating pivoted latch needles of a warp knitting machine along a knitting path from a low level in which the needles have drawn yarn for a new course of stitches through the stitches of a previously formed course and have cast off the previously formed course of stitches from the needles, to an intermediate level in which the stitches of the new course 3,570,269 Patented Mar. 16, 1971 have opened the latches of the needles and are positioned on the open latches, causing the needles to dwell in the intermediate level while yarns for another course of stitches are lapped around the needles between the hook portions and the open latches of the needles, and thence to a high level to clear the stitches of the new course below the open latches before the needles again return to a low level.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic elevational view of a portion of a warp knitting machine with means for operating the needles of the machine in accordance with the instant invention;

FIG. 2 is an end elevational view on an enlarged scale showing a portion of the stitch forming and yarn feeding elements of the machine of FIG. 1;

FIG. 3 is a view diagrammatically illustrating the path of movement of the needles along a line which is plotted in relationship to the angle of rotation of the operating shaft for the needles during stitch forming cycles thereof;

FIG. 4 is a view on an enlarged scale illustrating the relative positions of the stitch forming and yarn feeding elements at one stage of a stitch forming cycle thereof; and

FIGS. 5 and 8 are views similar to FIG. 4 showing the relative positions of the elements at other stages in the stitch forming cycle.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2 of the drawings there is shown a portion of a high speed warp knitting machine adapted to form courses of stitches of knitted fabric the machine including a latch needle 10, which is one of a row of such needles, having a hook portion 11 and a pivoted latch 12 for closing the hook portion. The machine also includes a bar 15 in which the needles are mounted, sinkers 16 in the spaces between the needles and yarn guides 17. The bar 15 is supported on levers, one of which is shown at 20 mounted for rocking movement on a shaft 21 whereby the needles are adapted to be operated along a knitting path as hereinafter set forth. The sinkers 16, which are provided with usual nebs 22, breast or knockover surfaces 25 and throats 26, are mounted in a bar 27 supported on rock levers 28 carried on a shaft 29 whereby the sinkers are operated in cooperation with the needles in forming the stitches of the knitted fabric. The yarn guides 17 are carried in bars 30 which are mounted on a rock shaft 31 for movement through and along the row of needles to lap yarns 35 (FIG. 2) fed by the guides around the needles to be formed into stitches by the needles.

Conventionally, during each knitting or course forming cycle of the machine the needles 10, sinkers 16 and yarn guides 17 are operated along cooperating paths to form stitches of yarns 3-5 fed by the yarn guides to the needles, with the needles rising from a low level following drawing yarn for a course of stitches to a high level. During this movement of the needles from the low to high levels the sinkers 16 are advanced to engage and hold the new stitches in the sinker throats 26 and the newly formed stitches open the latches 12 of the needles and thereafter are cleared below the opened latches. The guides are then operated through and along the needle row while the needles are at the high level to lap yarn for the next course of stitches around the needles between the hooks and open latches thereof. The needles are then lowered from the high level to the low level to draw yarn for the next course of stitches and cast the previously formed stitches therefrom. Very often due to the pressure exerted by the stitches on the open latches of the needles as the stitches are cleared the latches tend to fiy to closed position. When this occurs the yarn is lapped around the closed latches and no stitches are formed by the needles. Heretofore, in order to overcome this condition the machine was provided with a guard member which was moved between an active position to prevent the latches from closing during stitch clearing and an inactive position to permit the latches to be closed by the cleared stitches as the needles were lowered to form the new stitches.

In accordance with the instant invention the latches of the needles are retained in open position during the yarn lapping operation of the yarn guides without the use of the conventional latch guard. To achieve this result the needles 10 are adapted to be operated by a crank shaft 36 through mechanism as shown in FIG. 1 of Pat. No. 3,375,682. This mechanism has been diagrammatically illustrated in FIG. 1 herein for the purposes of simplicity as a crank 37 and a link 38 connecting the crank shaft 36 and the levers 20. The levers 20 are operated by the crank shaft, through crank 37 and link 38, to move the needles 10 along a knitting path illustrated by the dot-and-dash line 40 in FIG. 2 and as indicated in the curve 41 in FIG. 3 which is plotted in relationship to the angle of rotation of the crankshaft during stitch forming cycles thereof. The movement of the needles along the path 40 is from a low level 42 at point a on the curve to an elevated intermediate level 45 at point I). The needles 10 momentarily dwell at the intermediate elevated level 45 between the point 12 and a point and then rise to a further elevated highlevel 46 at point d. From the high level the needles are again lowered to the low level at point a in the curve. The needles are moved along the knitting path 40 between the low, intermediate and high levels for purposes hereinafter set forth.

During each knitting cycle of the machine the needles are moved from the high level to the low level to draw yarn for a new course of stitches, indicated at 50 in FIG. 4-, through a previously formed course of stitches and to cause the latter to be cast or knocked off the needles. At this time the latches of the needles, which were closed by the previously formed stitches, remain closed, the sinkers have been partially advanced to position the nebs 22 thereof over the previously formed stitches and also over the yarn for the new course of stitches, and the yarn guides 17 are in their normal position of rest to the left of the needle row. As the needles move from the low level shown in FIG. 4, corresponding to level 42 of FIG. 3, to the intermediate level of FIG. 5, corresponding to level 45 of FIG. 3, the sinkers 16 are moved to their fully advanced positions to engage and hold the stitches of the course 50 in their throats 26, the stitches of the course 50 during this movement opening the latches 12 of the me dles. As indicated in FIG. 5, the lower ends of the opened latches are slightly below the throats 26 of the sinkers and the stitches of the course 50 overlie and hold the latches open in the intermediate level of the needles.

While the needles dwell in the intermediate level 45 and the needle latches 12 are maintained open by the stitches of the course 50, the yarn guides 17 are rocked through the needle row from the left to the right side thereof, as shown by the dotted line position of the guides in FIG. 6. The guides are then moved along the needle row and thence back to their position of rest at the left side of the needle row to lap yarns 35 around the needles between the hook portions 11 and open latches 12 thereof for the next course of stitches. The needles then rise to the high level of FIG. 7 corresponding to the level 46 of FIG. 3, to clear the stitches of the course 50' to a position on the needles below the open latches. As the needles are lowered from the high level of FIG. 7 to the level of FIG. 8, which shows the position of the needles at a point e in the curve 41 (FIG. 3), the cleared stitches of the course 50 close the latches 12 over the hook portions 11 of the needles and the sinkers are moved to their retracted position before the needles reach their low level of FIG.

4. Thereafter as the needles continue from the level of FIG. 8 to the low level of FIG. 4 to draw yarn for the next course of stitches through the stitches of the course 50 the stitches of the course 50 are knocked off the needles and the sinkers are again partially advanced to position the nebs 22 over the yarn for the new course of stitches before the needles again rise from the low to the intermediate level of FIG. 5.

It is believed to be obvious from the foregoing that the instant invention provides an operating path for pivoted latch needles of a Warp knitting machine the path including a low level to which the needles move in drawing yarn for each new course of stitches, an intermediatte dwell level in which the latches of the needles are opened and maintained in open position by the stitches of the new course while yarn is lapped around the needles for the next course of stitches and a high level to which the needles are moved to clear the new course of stitches below the open latches before the needles again return to the low level to draw yarn for the next course of stitches and cast off the previously formed course of stitches.

It will be understood that the improvement specifically shown and described by which the above results are obtained, can be changed and modified in various ways without departing from the invention herein disclosed and hereinafter claimed.

What is claimed is:

1. In a warp knitting machine having a row of pivoted latch needles, sinkers for cooperation with said needles, and yarn guides for feeding yarns to said needles to be formed thereby into courses of stitches of a fabric, the improvement comprising means for moving said needles along a path from a low level, to which said needles were moved in drawing yarn for stitches of a first course of said fabric, to an intermedaite level in which said stitches of said first course rest on open latches of said needles, means for causing said needles to dwell in said intermediate level to maintain said latches open While said yarn guides lap yarns fed thereby around said needles for stitches of a second course of said fabric, means for moving said needles to a high level in said path during which movement said stitches of said first course are cleared below said open latches, and means for moving said needles from said high level to said low level to draw yarn for said stitches of said second course through said stitches of said first course and to cast off said stitches of said first course from said needles.

2. A machine according to claim 1, in which said sinkers have a neb and a throat portion, the lower ends of said open latches being below said throat portions of said sinkers and said throat portions acting to position said stitches of said first course on said open latches when said needles are in said intermediate level.

3. A method of knitting fabric on a warp knitting machine having a row of pivoted latch needles, yarn guides for lapping yarn around said needles to be formed thereby into courses of stitches of said fabric, and sinkers cooperating with said needles during formation of said courses of stitches by said needles including the steps of (a) raising said needles from a low level in which the latches of said needles are closed over the stitches of a first course of said fabric lying in the hooks of said needles to an intermediate level during which movement said stitches of said first course open said latches and become positioned on said open latches.

(b) causing said needles to dwell in said intermediate level,

(c) moving said yarn guides to lap yarns for stitches of a second course around said needles between said hook portions and said open latches of said needles while said needles dwell in said intermediate level,

(d) raising said needles from said intermediate level to a high level and clearing said stitches of said first course below said open latches of said needles, and

(e) lowering said needles from said high level to said low level and drawing said yarns lapped around said needles through said stitches of said first course and forming said yarns into stitches of said second course, said stitches of said first course also closing said latches and being cast off said needles during movement of said needles from said high to said low level.

4. A method according to claim 3 including the additional steps of (f) advancing said sinkers to hold said stitches of said 10 first course in throat portions of said sinkers as said needles are raised from said low level to said intermediate level and from said intermediate level to said high level, and

draw said yarn for said stitches of said second course over knockover surfaces of said sinkers and said knockover surfaces acting to cast said stitches of said first course from said needles during movement of said needles from said high to said low levels.

References Cited UNITED STATES PATENTS 3,375,682 4/1968 Wenrich 6686 FOREIGN PATENTS 1,079,261 4/ 1960 Germany 6686 (g) retracting said sinkers to cause said needles to 15 RONALD FELDBAUM, Primary Examiner 

